By my count, that's probably close to $1,000,000 in non income/cash flow producing debt. 

@Chris Schoonhoven, Columbus Ohio is a great RE market.Speaking of Hilltop, you need to find the sweet spot, I own duplex there and is one of my favorite, not really in Westgate, but that particular block is nice with home owners who take care of their properties, purchasing price is low, tenants there are low-income working class, I did serious tenants screening, and am very happy with the ones I have, it produce the most profit out of all my investments.

Keep in mind Americans are consumers, not producers.

This  would allow me to pay down an additional $40,000 of debt, leaving more funds from the cash out refi for rehabbing a non-income-producing garden unit in another building that I have sitting there.

Only funds placed into an OZ within 180 days of the sale that produced a capital gain are eligible for the OZ tax benefits. 

Think bigger than that, put your money to work for you and buy income producing assets or invest in other ways that earns more than what you’re paying for on your mortgage.

Question to the apartment owners, management companies, single family portfolio investors and the like.Would installing solar panels on your income producing assets make sense if there was no upfront installation cost and you could "bill" the customer for electricity that the sun produces for each property?

I am exploring MTRs and also browsing through realtor apps to see if there are multifamily homes in market that can produce cash flow.

Don't ever sell a property unless you have a concrete plan to invest the money somewhere else that will produce a greater return.Rent the entire house.

If you don't set internal deadlines and goals, before you know it, years will pass by and you will still have these vacant lots that are not producing cash flow or building your networth to the way you dreamed of.